If I'm not sure what layer a package in my 'package-selected-packages value comes from but I want to trim it down how would I go about that, like preventing load of packages on emacs load

I have about 315 installed packages

Cleaning up package-selected-packages wouldn’t reduce the load time though. If you really want to speed up the startup time maybe check pdumper stuff. If you simply annoyed that it keeps appending to that list and keeps it in your config, there is a way to force it to be in a separate file

(setq custom-file "~/.spacemacs.d/custom.el") (load custom-file)

oh I know, I mean just reduce the amount of elements being loaded. I know that variable is only so it' won't delete them from the melpa folder